Autoranging True RMS-to-DC Converter

A programmable gain amplifier (LTC6910-2) and a window comparator (LTC6700-1) and some control logic creates a wide dynamic range RMS to DC converter. The comparator monitors the DC output and signals whether to increment or decrement the gain to maintain a predetermined output voltage range. Knowing the output DC voltage and the gain setting can determine the True RMS amplitude of the signal being monitored.